A ball bearing that is adapted to be mounted on a shaft to permit linear movements is disclosed in German Offenlungsschrift No. 40 15 124. This known type of ball bearing includes a cage provided with guide tracks and return tracks that receive balls, and ball track plates that are positioned in recesses circumferentially disposed about the cage. The ball track plates are provided with lateral beads that fit into the recesses in the cage. The guide walls of the guide tracks and the return tracks are adapted to the size of the balls, with both the guide tracks and the return tracks having a slit that opens radially inwardly towards the shaft. In the radially outward direction, the guide tracks are covered by the ball track plates and the return tracks are covered by the cage jacket.
In this known design, the cross-section of the cage in the area of the guide tracks differs from the cross-section of the cage in the area of the return tracks. That is, the cage in the area of the guide tracks has a different material thickness than in the area of the return tracks. When the cage is produced from plastic material by injection molding, distortion can occur during manufacturing. Also, it must be determined from the start where the guide tracks and return tracks are to be located or distributed along the circumference of the cage. This means that different cage designs must be produced for different arrangements in spite of identical cage dimensions. This requires a higher expenditure for injection tools, and increases manufacturing costs and stock-keeping costs.
A need thus exists for a way of producing a linear movement ball bearing (i.e., a ball bearing that is adapted to permit linear movements) in which the essential component of the ball bearing, i.e. the cage, can be economically produced with relatively simple tools.
A need also exists for a way of producing a linear movement ball bearing which offers the possibility of producing different alternatives of the ball bearing with a customized arrangement of the load-bearing ball rows along the circumference, while using the same basic cage.